What desktop computer is best for faster rendering(preview and final) when you have lots of geometry to render like hair and fur?
Not enough details. You must mention the software you’re referring to, your budget, if you need a full system with peripherals, etc. The most important thing is the rendering software. Are you interested in cpu or gpu rendering?
I agree. Not enough details.
But in general, I can suggest some random machine for rendering.
CPU: 8-core with hyperthreading. Ryzen 7 1700 or better would be a good start.
Motherboard: B350, B450, X370, X470 chipsets depending on budget and various features required
RAM: 8GB dual-channel kit is a minimum
Cooling: any cooler that will cool down your CPU 24/7
SSD 1: NVME m.2 for system and main software
SSD 2 (optional): another NVME m.2 or SATA 3 with higher capacity for working projects
HDD: anything you want.
GPU: depending on rendering you will do. Choose the one that fits your budget best.
PSU: depending on general power consumption of your system when full loaded. I’d suggest at least 650W with 80+ Gold certificate. It will give you stable voltage on heavy mode load and external protection.
Case: anything with good airflow
It really depends on what application you plan to use to render. Most are still reliant on CPU core count but more are beginning to leverage GPU. Please let us know which applicaiton you plan to use and also what budget range you have in mind.